The Great Wall of China is a series of fortifications made
of stone, brick, tamped
earth, wood, and other
materials, generally built along an east-to-west line across the historical
northern borders of China to protect the Chinese states and empires against
the raids and invasions of the various nomadic groups of the Eurasian Steppe.
Several walls were being built as early as the 7th century BC; these,
later joined together and made bigger and stronger, are now collectively
referred to as the Great Wall. Especially famous is the wall built
220–206 BC by Qin Shi Huang,
the first Emperor of China. Little of that wall remains. Since then, the Great
Wall has been rebuilt, maintained, and enhanced; the majority of the existing
wall is from the Ming
Dynasty (1368–1644).
Other purposes of the Great Wall have
included border controls, allowing the imposition of duties on goods transported
along the Silk Road, regulation or encouragement of trade and the control of
immigration and emigration. Furthermore, the defensive characteristics of the
Great Wall were enhanced by the construction of watch towers, troop barracks,
garrison stations, signaling capabilities through the means of smoke or fire,
and the fact that the path of the Great Wall also served as a transportation
corridor.
The Great Wall stretches from Dandong in the east to Lop
Lake in the west,
along an arc that roughly delineates the southern edge of Inner Mongolia.
A comprehensive archaeological survey, using advanced technologies, has
concluded that the Ming walls measure 8,850 km (5,500 mi). This
is made up of 6,259 km (3,889 mi) sections of actual wall,
359 km (223 mi) of trenches and 2,232 km (1,387 mi) of
natural defensive barriers such as hills and rivers. Another
archaeological survey found that the entire wall with all of its branches
measure out to be 21,196 km (13,171 mi).
Names
The collection of fortifications now known as
"The Great Wall of China" has historically had a number of different
names in both Chinese and English.
In Chinese histories, the term
"Long Wall(s)" (長城, changcheng) appears in Sima Qian's Records of the
Grand Historian, where it referred to both the separate great walls built
between and north of the Warring States and to the more unified
construction of the First Emperor. The Chinese character 城 is a phono-semantic compound of the "place" or "earth" radical 土 and 成, whose Old Chinesepronunciation has been reconstructed as *deŋ. It
originally referred to the rampart which surrounded traditional Chinese cities and was used
by extension for these walls around their respective states; today, however,
it is much more often simply the Chinese word for "city".
The longer Chinese name "Ten-Thousand-Mile Long Wall" (萬里長城, Wanli
Changcheng) came from Sima Qian's description of it in the Records, though he did not
name the walls as such. The ad 493 Book of Song quotes the
frontier general Tan Daoji referring to
"the long wall of 10,000 miles", closer to the modern name, but the
name rarely features in pre-modern times otherwise. The traditional Chinese mile (里, lǐ) was an often irregular distance that
was intended to show the length of a standard village and varied with terrain
but was usually standardized at distances
around a third of an English mile (540 m). Since
China's metrication in 1930, it
has been exactly equivalent to 500 metres or 1,600 feet, which would make
the wall's name describe a distance of 5,000 km (3,100 mi). However,
this use of "ten-thousand" (wàn) is figurative in a similar
manner to the Greek and English myriad and simply means
"innumerable" or "immeasurable".
Because of the wall's association with the
First Emperor's supposed tyranny, the Chinese dynasties after Qin usually avoided referring to their own additions to the
wall by the name "Long Wall". Instead, various terms were used
in medieval records, including "frontier(s)" (塞, sāi), "rampart(s)" (垣, yuán), "barrier(s)" (障, zhàng), "the outer
fortresses" (外堡, wàibǎo), and "the border
wall(s)" (t 邊牆, s 边墙, biānqiáng). Poetic and
informal names for the wall included "the Purple Frontier" (紫塞, Zǐsāi) and
"the Earth Dragon" (t 土龍, s 土龙, Tǔlóng). Only during
the Qing period did
"Long Wall" become the catch-all term to refer to the many border
walls regardless of their location or dynastic origin, equivalent to the
English "Great Wall".
The current English name evolved from accounts
of "the Chinese wall" from early modern European
travelers. By the 19th century, "The Great Wall of China"
had become standard in English, French, and German, although other European
languages continued to refer to it as "the Chinese wall".
History
Early walls
The Chinese were already familiar with
the techniques of wall-building by the time of the Spring and Autumn period between the 8th and 5th
centuries BC. During this time and the subsequent Warring States period, the states of Qin, Wei, Zhao, Qi, Yan, and Zhongshan[20][21] all constructed extensive
fortifications to defend their own borders. Built to withstand the attack of
small arms such as swords and spears, these walls were made mostly by stamping
earth and gravel between board frames.
King Zheng of Qin conquered the last of his
opponents and unified China as the First Emperor of
the Qin dynasty ("Qin Shi Huang") in 221 BC. Intending
to impose centralized rule and prevent the resurgence of feudal lords, he
ordered the destruction of the sections of the walls that divided his empire
among the former states. To position the empire against the Xiongnu people from the north, however, he
ordered the building of new walls to connect the remaining fortifications along
the empire's northern frontier. Transporting the large quantity of materials
required for construction was difficult, so builders always tried to use local
resources. Stones from the mountains were used over mountain ranges,
while rammed earth was used for construction in the plains. There are no
surviving historical records indicating the exact length and course of the Qin
walls. Most of the ancient walls have eroded away over the centuries, and very
few sections remain today. The human cost of the construction is unknown, but
it has been estimated by some authors that hundreds of thousands, if not
up to a million, workers died building the Qin wall. Later, the Han, the Sui, and the Northern dynasties all
repaired, rebuilt, or expanded sections of the Great Wall at great cost to
defend themselves against northern invaders. The Tang and Song dynasties did not undertake any
significant effort in the region. The Liao, Jin, and Yuan dynasties, who ruled Northern China throughout most of the
10th–13th centuries, constructed defensive walls in the 12th century but those
were located much to the north of the Great Wall as we know it, within China's
province of Inner Mongolia and in Mongolia itself.
Ming era
The Great Wall concept was revived again
under the Ming in the 14th century, and following the Ming army's defeat by
the Oirats in the Battle of Tumu.
The Ming had failed to gain a clear upper hand over the Mongolian tribes after successive battles,
and the long-drawn conflict was taking a toll on the empire. The Ming adopted a
new strategy to keep the nomadic tribes out by constructing walls along the
northern border of China. Acknowledging the Mongol control established in
the Ordos Desert, the wall followed the desert's southern edge instead of
incorporating the bend of the Yellow
River.
Unlike the earlier fortifications, the
Ming construction was stronger and more elaborate due to the use of bricks and
stone instead of rammed earth. Up to 25,000 watchtowers are estimated to have
been constructed on the wall. As Mongol raids continued
periodically over the years, the Ming devoted considerable resources to repair
and reinforce the walls. Sections near the Ming capital of Beijing were
especially strong. Qi
Jiguang between
1567 and 1570 also repaired and reinforced the wall, faced sections of the
ram-earth wall with bricks and constructed 1,200 watchtowers from Shanhaiguan
Pass to Changping to warn of approaching Mongol raiders. During the
1440s–1460s, the Ming also built a so-called "Liaodong Wall". Similar
in function to the Great Wall (whose extension, in a sense, it was), but more
basic in construction, the Liaodong Wall enclosed the agricultural heartland of
the Liaodong province, protecting it against potential incursions by
Jurched-Mongol Oriyanghan from the northwest and the Jianzhou Jurchens from
the north. While stones and tiles were used in some parts of the Liaodong Wall,
most of it was in fact simply an earth dike with moats on both sides.
Towards the end of the Ming, the Great
Wall helped defend the empire against the Manchu invasions that began around 1600.
Even after the loss of all of Liaodong, the Ming army held the heavily
fortified Shanhai Pass, preventing the Manchus from conquering the Chinese
heartland. The Manchus were finally able to cross the Great Wall in 1644, after
Beijing had already fallen to Li
Zicheng's rebels.
Before this time, the Manchus had crossed the Great Wall multiple times to
raid, but this time it was for conquest. The gates at Shanhai Pass were opened
on May 25 by the commanding Ming general, Wu
Sangui, who formed an
alliance with the Manchus, hoping to use the Manchus to expel the rebels from
Beijing. The Manchus quickly seized Beijing, and eventually defeated both
the rebel-founded Shun
dynasty and
the remaining Ming resistance, establishing the Qing
dynasty rule over
all of China.
Under Qing rule, China's borders
extended beyond the walls and Mongolia was annexed into the empire, so
constructions on the Great Wall were discontinued. On the other hand, the
so-called Willow Palisade, following a line similar to that of the Ming Liaodong Wall,
was constructed by the Qing rulers in Manchuria. Its purpose, however, was not
defense but rather migration control.
None of the Europeans who visited Yuan China or Mongolia, such as Marco
Polo, Giovanni da Pian del Carpine, William of Rubruck, Giovanni de' Marignolli and Odoric of Pordenone, mentioned the Great Wall.
The North African traveler Ibn
Battuta, who also
visited China during the Yuan
dynasty ca. 1346, had heard about China's
Great Wall, possibly before he had arrived in China. He wrote that the wall is
"sixty days' travel" from Zeitun (modern Quanzhou) in his travelogue Gift to Those Who Contemplate the Wonders of Cities and the
Marvels of Travelling.
He associated it with the legend of the wall mentioned
in the Qur'an, which Dhul-Qarnayn (commonly associated with Alexander the Great) was said to have erected to protect people near the land of
the rising sun from the savages of Gog and Magog.
However, Ibn Battuta could find no one who had either seen it or knew of anyone
who had seen it, suggesting that although there were remnants of the wall at
that time, they weren't significant.
Soon after Europeans reached Ming China
by ship in the early 16th century, accounts of the Great Wall started to
circulate in Europe, even though no European was to see it for another century.
Possibly one of the earliest European descriptions of the wall and of its
significance for the defense of the country against the "Tartars" (i.e. Mongols), may be the one
contained in João de Barros's 1563 Asia. Other early accounts in Western sources include those
of Gaspar da Cruz, Bento de Goes, Matteo
Ricci, and Bishop Juan González de Mendoza. In 1559, in his work "A
Treatise of China and the Adjoyning Regions," Gaspar da Cruz offers an
early discussion of the Great Wall. Perhaps the first recorded instance of a
European actually entering China via the Great Wall came in 1605, when the
Portuguese Jesuit brother Bento de Góis reached
the northwestern Jiayu Pass from India. Early European accounts were mostly
modest and empirical, closely mirroring contemporary Chinese understanding of
the Wall, although later they slid into hyperbole, including the erroneous
but ubiquitous claim that the Ming Walls were the same ones that were built by
the First Emperor in the 3rd century BC.
When China opened its borders to foreign
merchants and visitors after its defeat in the First and Second Opium Wars,
the Great Wall became a main attraction for tourists. The travelogues of the
later 19th century further enhanced the reputation and the mythology of the
Great Wall, such that in the 20th century, a persistent misconception
exists about the Great Wall of China being visible from the Moon or even Mars.
Although a formal definition of what constitutes a
"Great Wall" has not been agreed upon, making the full course of the
Great Wall difficult to describe in its entirety, the course of the main
Great Wall line following Ming constructions can be charted.
The Jiayu Pass, located in Gansu province, is the western
terminus of the Ming Great Wall. Although Han fortifications such as Yumen Passand the Yang Pass exist further west, the extant walls
leading to those passes are difficult to trace. From Jiayu Pass the wall
travels discontinuously down the Hexi Corridor and into the deserts of Ningxia, where it enters the western edge of the
Yellow River loop at Yinchuan. Here the first major walls erected during the
Ming dynasty cuts through the Ordos Desert to the eastern edge of the
Yellow River loop. There at Piantou Pass (t 偏頭關, s 偏头关, Piāntóuguān) in Xinzhou, Shanxi province, the Great Wall splits in two
with the "Outer Great Wall" (t 外長城, s 外长城, Wài
Chǎngchéng) extending along the Inner Mongolia border
with Shanxi into Hebei province, and
the "inner Great Wall" (t 內長城, s 內长城, Nèi
Chǎngchéng) running southeast from Piantou Pass for some
400 km (250 mi), passing through important passes like the Pingxing Pass and Yanmen Pass before joining the Outer Great Wall at
Sihaiye (四海冶, Sìhǎiyě), in Beijing's Yanqing County.
The sections of the Great Wall around
Beijing municipality are especially famous: they were frequently renovated and
are regularly visited by tourists today. The Badaling Great Wall near Zhangjiakou is the most famous stretch of the
Wall, for this is the first section to be opened to the public in the People's
Republic of China, as well as the showpiece stretch for foreign
dignitaries. South of Badaling is the Juyong
Pass; when used by the
Chinese to protect their land, this section of the wall had many guards to
defend China's capital Beijing. Made of stone and bricks from the hills, this
portion of the Great Wall is 7.8 m (25 ft 7 in) high and
5 m (16 ft 5 in) wide.
One of the most striking sections of the Ming
Great Wall is where it climbs extremely steep slopes in Jinshanling. There it runs 11 km (7 mi) long,
ranges from 5 to 8 m (16 ft 5 in to 26 ft 3 in) in
height, and 6 m (19 ft 8 in) across the bottom, narrowing up to
5 m (16 ft 5 in) across the top. Wangjinglou (t 望京樓, s 望京楼, Wàngjīng Lóu) is one of
Jinshanling's 67 watchtowers, 980 m
(3,220 ft) above sea level. Southeast of Jinshanling is the Mutianyu Great Wall which winds along lofty,
cragged mountains from the southeast to the northwest for 2.25 km
(1.40 mi). It is connected with Juyongguan Pass to the west and Gubeikou
to the east. This section was one of the first to be renovated following the
turmoil of the Cultural Revolution.
At the edge of the Bohai Gulf is Shanhai Pass,
considered the traditional end of the Great Wall and the "First Pass Under Heaven". The part of the wall inside Shanhai
Pass that meets the sea is named the "Old Dragon Head". 3 km
(2 mi) north of Shanhai Pass is Jiaoshan Great Wall (焦山長城), the site of the
first mountain of the Great Wall. 15 km (9 mi) northeast from
Shanhaiguan is Jiumenkou (t 九門口, s 九门口, Jiǔménkǒu), which is the
only portion of the wall that was built as a bridge. Beyond Jiumenkou, an
offshoot known as the Liaodong Wall continues through Liaoning province and terminates at the Hushan Great Wall, in the city of Dandong near the North Korean border.[52]
In 2009, 180 km of previously
unknown sections of the wall concealed by hills, trenches and rivers were
discovered with the help of infrared range finders and GPS devices. In March and April
2015 nine sections with a total length of more than 10 km (6 mi),
believed to be part of the Great Wall, were discovered along the border
of Ningxia autonomous region and Gansu province.
Characteristics
Before the use of bricks, the Great Wall
was mainly built from rammed earth, stones, and wood. During the Ming, however,
bricks were heavily used in many areas of the wall, as were materials such as
tiles, lime, and stone. The size and weight of the bricks made them easier to work
with than earth and stone, so construction quickened. Additionally, bricks
could bear more weight and endure better than rammed earth. Stone can hold
under its own weight better than brick, but is more difficult to use.
Consequently, stones cut in rectangular shapes were used for the foundation,
inner and outer brims, and gateways of the wall. Battlements line the uppermost portion of the
vast majority of the wall, with defensive gaps a little over 30 cm
(12 in) tall, and about 23 cm (9.1 in) wide. From the parapets,
guards could survey the surrounding land. Communication between the army
units along the length of the Great Wall, including the ability to call
reinforcements and warn garrisons of enemy movements, was of high
importance. Signal towers were built upon hill tops or other high points along
the wall for their visibility. Wooden gates could be used as a trap against
those going through. Barracks, stables, and armories were built near the wall's
inner surface.
Condition
While portions north of Beijing and near
tourist centers have been preserved and even extensively renovated, in many
other locations the Wall is in disrepair. Those parts might serve as a village
playground or a source of stones to rebuild houses and roads. Sections of
the Wall are also prone to graffiti and vandalism, while inscribed bricks were pilfered
and sold on the market for up to 50 renminbi. Parts have been destroyed because
the Wall is in the way of construction. A 2012 report by the State Administration of Cultural Heritage states that 22% of the Ming Great
Wall has disappeared, while 1,961 km (1,219 mi) of wall have
vanished. More than 60 km (37 mi) of the wall in Gansu province may disappear in the next
20 years, due to erosion from sandstorms. In some places, the height of the wall
has been reduced from more than 5 m (16 ft 5 in) to less than
2 m (6 ft 7 in). Various square lookout towers that characterize
the most famous images of the wall have disappeared. Many western sections of
the wall are constructed from mud, rather than brick and stone, and thus are more
susceptible to erosion. In 2014 a portion of the wall near the border of
Liaoning and Hebei province was repaired with concrete. The work has been much
criticized.
Visibility from space
From the Moon
One of the earliest known references to
the myth that the Great Wall can be seen from the moon appears in a letter written in
1754 by the English antiquary William Stukeley.
Stukeley wrote that, "This mighty wall of
four score miles [130 km] in length is only exceeded by the Chinese Wall,
which makes a considerable figure upon the terrestrial globe,
and may be discerned at the Moon. The claim was also mentioned by Henry Norman in 1895 where he states "besides its age it enjoys
the reputation of being the only work of human hands on the globe visible from
the Moon. The issue of "canals" on Mars was prominent in the late 19th century and may have led
to the belief that long, thin objects were visible from space. The claim that
the Great Wall is visible from the moon also appears in 1932's Ripley's Believe It or Not! strip and in Richard Halliburton's 1938 book Second Book of Marvels.
The claim the Great Wall is visible from the moon has
been debunked many times, but is still ingrained in popular culture. The
wall is a maximum 9.1 m (29 ft 10 in) wide, and is about the
same color as the soil surrounding it. Based on the optics of resolving power
(distance versus the width of the iris: a few millimeters for the human eye,
meters for large telescopes) only an object of reasonable contrast to its
surroundings which is 110 km (70 mi) or more in diameter (1 arc-minute)
would be visible to the unaided eye from the Moon, whose average distance from
Earth is 384,393 km (238,851 mi). The apparent width of the Great
Wall from the Moon is the same as that of a human hair viewed from 3 km
(2 mi) away. To see the wall from the Moon would require spatial
resolution 17,000 times better than normal (20/20) vision. Unsurprisingly,
no lunar astronaut has ever claimed to have seen the Great Wall from the Moon.
A more controversial question is whether
the Wall is visible from low Earth orbit (an
altitude of as little as 160 km (100 mi)). NASA claims that it is barely visible,
and only under nearly perfect conditions; it is no more conspicuous than many
other man-made objects. Other authors have argued that due to limitations
of the optics of the eye and the spacing of photoreceptors on
the retina, it is impossible to see the wall with the naked eye, even
from low orbit, and would require visual acuity of
20/3 (7.7 times better than normal).
Astronaut William Pogue thought
he had seen it from Skylab but discovered he was actually looking at the Grand Canal of China near Beijing. He spotted the Great Wall with
binoculars, but said that "it wasn't visible to the unaided eye."
U.S. Senator Jake Garn claimed to be able to see the Great Wall with the naked
eye from a space shuttle orbit in the early 1980s, but his claim has been
disputed by several U.S. astronauts. Veteran U.S. astronaut Gene Cernan has
stated: "At Earth orbit of 100 to 200 miles [160 to 320 km] high, the
Great Wall of China is, indeed, visible to the naked eye." Ed Lu, Expedition
7 Science Officer
aboard the International Space Station, adds that, "it's less visible
than a lot of other objects. And you have to know where to look."
In 2001, Neil Armstrong stated
about the view from Apollo
11: "I do not
believe that, at least with my eyes, there would be any man-made object that I
could see. I have not yet found somebody who has told me they've seen the Wall
of China from Earth orbit. ... I've asked various people, particularly Shuttle
guys, that have been many orbits around China in the daytime, and the ones I've
talked to didn't see it."
In October 2003, Chinese astronaut Yang
Liwei stated that
he had not been able to see the Great Wall of China. In response, the European Space Agency (ESA) issued a press release
reporting that from an orbit between 160 and 320 km (100 and 200 mi),
the Great Wall is visible to the naked eye, even though the ISS is in low Earth
orbit , not space. In an attempt to further clarify things, the ESA published a
picture of a part of the "Great Wall" photographed from low orbit.
However, in a press release a week later, they acknowledged that the
"Great Wall" in the picture was actually a river.
Leroy
Chiao, a
Chinese-American astronaut, took a photograph from the International Space Station that shows the wall. It was so
indistinct that the photographer was not certain he had actually captured it.
Based on the photograph, the China Daily later reported that the Great Wall can be seen from 'space' with
the naked eye, under favorable viewing conditions, if one knows exactly where
to look. However, the resolution of a camera can be much higher than the
human visual system, and the optics much better, rendering photographic
evidence irrelevant to the issue of whether it is visible to the naked eye.